1. Field of the Invention
The invention relates to an apparatus for cutting slots in corrugated and twin-wall pipes.
2. Background Art
A device for the cutting of slots in pipes of cuttable material, in particular in plastics drain pipes, is known from U.S. Pat. No. 4,488,467. It has a cutter head, which is provided with at least one knife and which is positively driven by a planetary gear to move on rolling contact with the circumference of the pipe. The cutting edge of the knife rotates along an epitrochoid about the tube. The cutter head is provided with webs engaging with annular impressions in the external wall of the pipe. The cutter head is provided with helical webs, the at least one knife being arranged parallel to the webs. As a result, holes can be cut into pipes that have at least in part toroidal elevations and corresponding impressions along their circumference. These devices have been very successful in practice; their disadvantage resides in that, for pipes of great diameters, they become too complicated in construction.
A leaflet of UNICOR GmbH entitled "CORRUGATORS Production lines for large-sized corrugated pipes 65-420 mm o.d.", imprint 104/02/97/10.89/EA, discloses to use saws for the production of slots in the mentioned corrugated and twin-wall pipes. Six saws at maximum are applicable around the tube, which are pivoted about a frame axis in the direction towards and away from, the pipe. The pipe is retained during the sawing operation in the direction of its axis.